ATP binding to the ϵ subunit of F1-ATPase, a soluble subcomplex of TFoF1 (FoF1-ATPase synthase from the thermophilic Bacillus strain PS3), affects the regulation of F1-ATPase activity by stabilizing the compact, ATPase-active, form of the ϵ subunit [Kato, S., Yoshida, M. and Kato-Yamada, Y. (2007) J. Biol. Chem. 282, 37618–37623]. In the present study, we report how ATP binding to the ϵ subunit affects ATPase and H+ pumping activities in the holoenzyme TFoF1. Wild-type TFoF1 showed significant H+ pumping activity when ATP was used as the substrate. However, GTP, which bound poorly to the ϵ subunit, did not support efficient H+ pumping. Addition of small amounts of ATP to the GTP substrate restored coupling between GTPase and H+ pumping activities. Similar uncoupling was observed when TFoF1 contained an ATP-binding-deficient ϵ subunit, even with ATP as a substrate. Further analysis suggested that the compact conformation of the ϵ subunit induced by ATP binding was required to couple ATPase and H+ pumping activities in TFoF1 unless the ϵ subunit was in its extended-state conformation. The present study reveals a novel role of the ϵ subunit as an ATP-sensitive regulator of the coupling of ATPase and H+ pumping activities of TFoF1.
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Research Article|
June 14 2011
ATP binding to the ϵ subunit of thermophilic ATP synthase is crucial for efficient coupling of ATPase and H+ pump activities
Fumitaka Kadoya;
Fumitaka Kadoya
*Department of Life Science, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
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Shigeyuki Kato;
Shigeyuki Kato
*Department of Life Science, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
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Kei Watanabe;
Kei Watanabe
*Department of Life Science, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
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Yasuyuki Kato-Yamada
Yasuyuki Kato-Yamada
1
*Department of Life Science, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
†Frontier Project ‘Adaptation and Evolution of Extremophiles’, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
1To whom correspondence should be addressed (email katoyama@rikkyo.ac.jp).
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Publisher: Portland Press Ltd
Received:
March 09 2011
Revision Received:
April 12 2011
Accepted:
April 21 2011
Accepted Manuscript online:
April 21 2011
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© The Authors Journal compilation © 2011 Biochemical Society
2011
Biochem J (2011) 437 (1): 135–140.
Article history
Received:
March 09 2011
Revision Received:
April 12 2011
Accepted:
April 21 2011
Accepted Manuscript online:
April 21 2011
Citation
Fumitaka Kadoya, Shigeyuki Kato, Kei Watanabe, Yasuyuki Kato-Yamada; ATP binding to the ϵ subunit of thermophilic ATP synthase is crucial for efficient coupling of ATPase and H+ pump activities. Biochem J 1 July 2011; 437 (1): 135–140. doi: https://doi.org/10.1042/BJ20110443
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